Electron discharge device



May 5, 1964 J. B. WINK ETAL ELECTRON DISCHARGE DEVICE Filed 001;. 50. 1961 FIG.2

INVENTORS CONRAD L. HOWE JAMES B. WINK FIG. 5

United States Patent Qfifice 3,132,277 Patented May 5, 1964 3,132,277 ELECTRON DISCHARGE DEVICE James B. Wink, Owensboro, Ky., and Conrad L. Howe, Tell City, Ind, assignors to General Electric Company, a corporation of New York Filed Oct. 31), 1961, Ser. No. 148,324 11 Claims. (Cl. 313-146) This invention relates to electron discharge devices and, more particularly, to novel and improved anode structures for such devices.

In the assembly of many types of electron discharge devices, and particularly those having more than one grid electrode, it is important to insure a desired electrode alignment, such as a desired alignment of the elements of various grids. Failure to accurately align the grids with respect to each other can give rise to excessive grid current. Heretofore, in electron discharge devices, such as aligned grid type power pentodes, provision has been made for windows in the anode of the pentode to allow for visual inspection of the alignment of the grid elements. Such windows have been provided with a flap secured to or integral with one longitudinal edge of the window and adapted to be rotated to closed position over the window. In order to view the grids for checking alignment, a view perpendicular to the plane of the grids is required. Accordingly, such windows are commonly located in the anode and directly in the line of the greatest electron concentration. Thus, when the known type of alignmentwindow flap is open, it forms a relatively large angle with the associated surface of the anode so that it is difiicult to close the flap after electrode alignment, because of the spring of the material produced by the angle through which the flap must be closed.

Further, any attempt to secure the flap of the prior art in closed condition, as by welding it to the anode, results in damage to the surface of the anode from the pressure and heat applied during welding. Thus, since good sealing is not feasible, a residual opening, resulting from the spring of the material, is commonly present during the operation of the discharge device, which opening allows electrons from the cathode to pass through and tobombard the outer glass bulb. Such bulb bombardment during the normal life of the discharge device causes the absorbed gases of the glass to be released in the form of water vapor, carbon dioxide and nitrogen. The release of these gases has a poisoning effect upon the cathode that results in a lower value of transconductance and reduces the effective life of the discharge device.

A further problem has been noted, in the construction of certain electron discharge devices which require a radiating fin on the anode to improve 'heat dissipation. If the prior-art type of alignment window and flap heretofore described are used on such anodes, with the radiating fin disposed in the center of the anode for more efiicient operation, the window or windows, if more than one are used, are necessarily place-d on either side of the fin. Such an off-center placement positions the alignment window at an ineffective point on the anode structure from which to observe the grid alignment.

Accordingly, it is a principal object of the present invention to provide an improved electron discharge device anode arrangement from which the foregoing disadvantages have been eliminated and which facilitates the alignment of the grid electrodes enclosed by the anode during assembly of the device.

Another object of this invention is to provide an improved grid-controlled electron discharge device having a novel anode-window arrangement to facilitate the alignment of the grid electrodes within the anode enclosure during assembly.

Yet another object of the invention is to provide an electron discharge device having an improved anode-window arrangement useful for electrode alignment purposes, which window arrangement may be effectively completely closed after electrode alignment without damaging the anode structure.

A still further object of the invention is to provide an electron discharge device having an improved anode-Window arrangement useful for alignment purposes and so arranged as to provide additional anode cooling surfaces when closed after electrode alignment.

In order to attain the foregoing objects, a window is provided in the anode or shield of a discharge device, which will allow a perpendicular view of the plane of the interior electrodes such as grids or the like, when aligning the electrodes during assembly. The window is provided with flaps secured to or integral with the anode adjacent the sides of the window, preferably parallel to the longitudinal axis of the discharge device. The anode surfaces and the alignment-window flaps are so formed that the outer surface of each flap makes an obtuse angle with the adjacent portion of the outer surface of the anode. The obtuse angular position of the flaps minimizes strain on the surface of the anode when the flaps are subsequently bent to be joined and to close the window after electrode alignment. Further, the flaps can be spot welded together without any deformation of the anode, because the weld is not applied to any portion of the anode surface, but rather is applied to theadjoining flap surfaces. In

discharge devices having a radiating fin on the anode, the

alignment window is positioned to intersect the fin and each flap is formed with two sections so arranged that the first sectioncloses on the alignment window upon closing the flaps; and the second section conforms to the shape of the fin when the alignment window is closed.

For a better understanding of the invention, reference is made to the following description taken in connection 'with the accompanying drawings in which:

FIG. 1 is an elevational view, with parts broken away, of an electron discharge device embodying the anode arr-angement of the invention, with the alignment window flaps open and showing a view of the enclosed electrodes prior to final assembly of the device;

FIG. 2 is a cross-sectional view of the device of FIG. 1 taken along the line IIII thereof and in the direction of the arrows, after the device is rotated through degrees about its longitudinal axis;

FIG. 3 is a fragmentary perspective view of the anode of the device of FIG. 1 according to another embodiment of the invention;

FIG. 4 is a View similar to that of FIG. 3 with the alignment window flaps closed; and I FIG. 5 is a fragmentary top plan view of an anode for electron discharge devices showing yet another embodiment of the alignment-window flaps in open position.

Referring now to the drawing, and particularly FIGS. 1 and 2 thereof, there is shown an aligned-grid power pent ode 11 embodying the features of our invention and comprising an evacuated envelope 13 containing coaxially disposed electrode elements including a centrally disposed indirectly-heated cathode 15; control, screen and suppressor grids 17, 19, and 20, respectively, spaced outwardly from said cathode; and an anode 21 enclosing the foregoing elements. For reasons which will appear, anode 21 is formed to define, in cross-section, a substantially diamond-shaped enclosure, as shown more clearly in FIG. 2, the active, electron-intercepting surfaces of which are desirably formed by pairs of angularly disposed planar wall portions 23, 25 and 27, 29. Intermediate the electron-intercepting surfaces are anode portions 31, 33, which are here shown as plane parallel portions interconnecting the angulated active surfaces, but which {I} may, if desired, be of any other suitable configuration, as, for example, arcuate.

It should be understood that, while we have here selected a power pentode as the electron discharge type in which to disclose the features and advantages or" the novel anode arrangements to be described in detail hereinbelow, this selection is exemplary only, and that these features and advantages are equally available in any other type of electron discharge device wherein plural grids or other electrodes are provided, alignment of which, during assembly of the device is desired or required.

To permit visual inspection of the assembly of the grid elements 17, 119, and 20 for the purpose of ensuring alignment thereof or of any two of said elements, a window 35 is provided in one pair of adjacent active anode surfaces here shown to be in the surfaces 23, 25, the window being formed by cutting out portions of the surfaces 23, 25. At the lateral edges of the window 35, window-fitting and enclosing flaps 37 and 39 are hinged for easy rotation or displacement, the former being connected at the window edge in surface 23, the latter at the window edge in surface 25. The hinging of the flaps may be by brazing or the like, or the flaps may be formed integrally with the anode.

The flaps 37 and 39 are desirably formed with body portions 41, 43 dimensioned to fit snugly in the respective window openings in the anode surfaces 23 and 25. At the free ends of the body portions 41, 43, we provide offset tabs 45, 47, respectively, which may be integral with the respective body portions or suitably attached thereto. As shown, the tabs are angularly disposed relative the associated body portions 41, 43 so that when the latter are rotated or displaced into position to close the window portions, the tabs 45, 47 meet in the side-by-side relation in which position they may be secured together as by spot-welding or other suitable means.

'It will be noted that when the flaps 37 and 39 are bent to be joined to close the window 35 after electrode alignment has been accomplished, the initial obtuse angular open position of the flaps 37 and 39 prevents or minimizes the development of excessive strain on the active sur-' faces of the anode 23, 25. Further, the joining of the flaps 37 and 39 is accomplished without any deformation of the active anode surfaces, inasmuch as the weld is not applied to any portion of the said active surface of the anode, but rather is applied only to the adjoining flap edges. It will be seen that with the alignment-window flaps 37 and 39 open, a perpendicular view of the plane of the grid wires 17, 19 and 20 and the cathode 15 is provided through the window 35.

It will be appreciated that while the anode 21 has been shown in FIG. 1 in a glass enclosed device with flaps 37, 39 in open position so that a view of the grids and cathode is available through open window 35, this showing is merely schematic and does not represent an actual condition of a completely assembled device. The flaps are open only during alignment of the grids as required, whereupon they are closed-and sealed to the anode and thereafter the assembly is further processed by mounting on a stem and enclosed in envelope 13, evacuated and sealed.

We have hereinabove described an alignment-window flap arrangement for an anode window 35 having at least two opposite sides parallel to the longitudinal axis of the discharge device. As used in the present description and in the appended claims, the term longitudinal axis of the discharge device is considered as that axis which extends generally in the same direction as the axis of cathode of the discharge device. It will be understood that the alignment window need not have opposite sides parallel to each other or the longitudinal axis of the discharge device. Further, the alignment-window flaps need not be adjacent the sides of the alignment window that are parallel to the longitudinal axis of the discharge device as in the just-described embodiment of FIGS. land 2, but alternatively, the flaps may be hinged on the other two A opposite sides. Thus, in the two-flap arrangement of our invention, it is only essential that the flaps be hinged adjacent two opposing sides of the alignment window.

Considering the invention in its broadest aspect, it is not necessary that there be a two-flap arrangement so long as there is one flap forming, in open condition, an obtuse angle with the active surface of the anode, which orientation decreases or minimizes the strain produced on the surface of the anode, when the flap is subsequently rotated or displaced to close the window. In the preferred two-flap embodiment, it is noted that the obtuse angles are formed between the portions 23 and 25 of the anode 21 and the body portions 41 and 43, respectively, of the flaps 37 and 39. In this embodiment, the obtuse angles are readily achieved because of the angle at which the anode surfaces 23 and 25 are disposed with respect to each other. This angular arrangement of the surfaces 23 and 25 permits the formation of obtuse angles when flaps 37 and 39 are open and yet allows an adequate view through a normal sized alignment window 35. If the active surfaces of anode 21 were of some other com figuration such as would result from coplanar active surfaces, the window 35 would have to be larger to allow the obtuse angles to be formed between the outer planar surfaces of the anode and the outer surface of the flaps 37 and 39 and yet provide an adequate view through the alignment window 35.

In FIGS. 3 and 4, there are shown fragmentary views of the open and closed positions, respectively, of an arrangement of window flaps for an anode 51 of a discharge device having a heat radiating fin or flange 53 to improve heat dissipation from the anode. Anode construction with such fins is desirable even where added heat dissipation from the anode is not required, the fin in such structures resulting from the joining of two anode halves. In anodes of this type, the alignment-window flaps are similarly formed with two portions for each flap, e.g., body portions 55, 57 and tab portions 59, 61, respectively. The alignment window 63, it will be observed, intersects or is formed through the fin 53 as well as the active surfaces of the anode 51. Body portions 55 and 57 form obtuse angles with the associated anode surfaces to which they are hinged along their hinge or fold lines as at 65 and 67. The tabs 59, 61 are formed at such an angle to the associated body portions 55, 57 that when the flaps are closed, the tabs 59, 61 conform to the shape of the radiating fin 53 and provide additional cooling surfaces on the anode 4 from which heat may be dissipated. FIG. 4 illustrates the flaps in a closed position with tabs joined as by spot welding at points 63 and 65 to provide permanent sealing of the alignment window. The sealing may, of course, be by other well-known expedients, as for example, by staking. The sealing of the window by joining the tabs 59, 61, operates further to prevent the escape of electrons during operation of the discharge device thereby to avoid unwanted bombardment of the envelope 13 (FIG. 1) and the deleterious effects caused thereby.

FIG. 5 illustrates an anode portion 51 of a discharge device which is generally similar to that of FIG. 4 but showing an alternative embodiment of the alignmentwindow flaps in which one of the flaps is formed with a third section which, as shown, is a reversely bent end tab 71 integrally formed with or attached to tab 59 and which, when the flaps are closed, clamps over the tab 61 of the adjacent flap and also conforms to the shape of the radiating fin 53. Other parts of the arrangement of FIG. 5 which are similar to those shown in FIG. 4 are identified by reference numerals used in FIG. 4. The clamping of the tab 71 to the tab 61, it will be noted, further insures good sealing of the alignment window and prevents the escape of electrons.

While there has here been described an anode of a discharge device as having one alignment window and one set of alignmentwindow flaps, it will be understood that a plurality of such windows and associated flaps can be employed to provide several views of the electrodes for alignment purposes. Such plurality of windows can be arranged vertically, one above the other, or on opposite sides of the anode, or both. Further, while we have shown the alignment window in position to be bisected by the radiating fin 53, it will be understood that the radiating fin need not be disposed to so bisect the alignment window but may intersect some other portion of the window such that when the window is open a perpendicular view of the plane of the interior electrodes such as grids may be obtained. Further, if a perpendicular view of the plane of the grids or the electrodes is not necessary for alignment of the electrodes, then the alignment window may be placed at any suitable part or location in the anode or shield of the discharge devicef Although particular embodiments of the subject invention have been described, many modifications may be made and it is understood to be the intention of the appended claims to cover all such modifications which fall within the true spirit and scope of the invention.

What is claimed to be new and desired to be secured by Letters Patent of the United States is:

1. An electron discharge device having an anode including means defining a window, and a flap hinged to said anode along one side of said window and forming with said anode an obtuse angle in open position, said flap being movable to closed position.

2. An electron discharge device having an anode disposed along an axis thereof and including means defining a window having at least one side aligned with said axis, and closure means on said anode and disposed along said one side of said window and forming, in open position, an obtuse angle with the outer surface of the anode, said closure means being movable to close said window.

3. The device as defined in claim 2, wherein said closure means comprises a pair of flaps hinged to said anode along opposing sides of said window, each said flap forming obtuse angles with the associated outer surfaces of the anode.

4. An electron discharge device having an anode, a window in the anode having two sides aligned with the longitudinal axis of the discharge device, a pair of flaps hinged to said anode along said aligned sides of said window and each forming an angle with the outer surfaces of the anode along their hinge lines.

5. An electron discharge device having an anode, a window in the anode, a pair of flaps hinged to said anode along opposing sides of said window and each formed with an obtuse angle to the outer surfaces of the anode along their hinge lines to be movable to close said window, and means to join said flaps along their adjoining edges after movement of said flaps to close said window.

6. An electron discharge device having an anode, a window in the anode having at least two sides aligned with the longitudinal axis of the discharge device, a pair of flaps hinged to said anode along the aligned sides of said window and each formed with an obtuse angle to the outer surface of the anode along their hinge lines to be movable to close said window, and means to oin said flaps along their adjoining edges after movement of said outwardly therefrom, a window in the anode intersecting said fin, a plurality of-ilaps hinged to said anode along opposite sides of said window and bent to form at least first and second sections, the surfaces of one of said sections forming angles of predetermined magnitude with the outer surfaces of the anode along their hinge lines in open position of saidflaps and movable to close said window, the other sections being bent at angles to the first sections to conform to the shape of said after movement of said first sections to close said window.

8. The electron discharge device as defined in claim 7, further comprising means to join the other sections of the fiaps.

9. An electron discharge device comprising means dcfining a conductive'enclosure having in cross-section a substantially geometrically shaped configuration, a fin extendingalong said anode, a window in the anode intersecting said fin, a pair of flaps on said anode along the sides of said window parallel to said radiating tin and bent to form at least first and second sections, the enter surfaces of one of said sections of each flap forming in open position obtuse angles with the respective outer surfaces of the anode along their hinge lines and movable to closed position to close said window, the other sections being bent at'angles to the associated one sections to conform to the shape of said fin after movement of said one sections to close said window, and means to join the other sections of the flaps.

10. An electron discharge device having an anode, a radiating firi extending longitudinally along said anode, a window in the anode intersecting said radiating fin, a pair of flaps hinged to said anode along opposing sides of said Window and bent to form at least first and second sections, the outer surfaces of the first sections formed with an obtuse angle to the outer surfaces of the anode along their hinge lines to be movable to close said window, the second sections being bent at angles to the first sections to conform to the shape of said fin after movement of said first sections to close said window, and at least one of the flaps having a third section formed at an angle to the second section of the flap to be clamped over the second section of an adjacent flap to join the second sections of the flaps after movement of said first sections] 1 to close said window.

11. An electron discharge device having an anode, a radiating fin extending longitudinally along the anode, 'a

window in the anode intersecting said fin, a pair of flaps hinged to said anode along the sides of said window fin after movement of said first sections to close said 1 window, and at least one of the flaps having a third section formed at an angle to the second section of the flaptobe clamped over the second section of an adjacent flap to i oin the second sections of the .flaps after movement of 

1. AN ELECTRON DISCHARGE DEVICE HAVING AN ANODE INCLUDING MEANS DEFINING A WINDOW, AND A FLAP HINGED TO SAID ANODE ALONG ONE SIDE OF SAID WINDOW AND FORMING WITH SAID ANODE AN OBTUSE ANGLE IN OPEN POSITION, SAID FLAP BEING MOVABLE TO CLOSED POSITION. 